The present invention relates to a moving body track indicating system for indicating on the display surface of an indicator longitude and latitude line markers as well as the track of a moving body.
A moving body track indicating system typically includes a navigation aid apparatus as a Loran receiver, an Omega receiver or an NNSS (Navy Navigation Satellite System) receiver for measuring the positions of moving bodies. Such systems utilize the output signals from the receiver to successively plot the positions of the moving body in which the system is utilized on an indication medium such as a recording paper on which longitude and latitude line markers have been previously printed thereby indicating the track of the moving body thereon. Such a moving body track indicating system may be installed on moving bodies such as ships or airplanes. Hereinafter, the present invention will be described with reference to a ship track indicating system although, as explained above, the invention is not limited to that particular system.
Ship track indicating systems have been proposed and widely used in which a mechanically operated X-Y recorder successively plots the positions of a ship on a chart based on positional information supplied from a navigational aid device thereby tracing the ship's track on the chart. The X-Y recorder in these systems is operated in such a way that the recording pen thereof is moved in X and Y directions through distances determined both by the distance difference between a reference point and the ship's position and by the scale of the chart used. In operation, complicated adjustments must firstly manually be made to establish a reference point on the chart and to determine the amount of movement of the recording pen in accordance with the map scale selected. Further, when a magnified or reduced pattern of the ship's track is desired to be recorded on the recording paper, the amount of travel of the recording pen must be manually re-adjusted. The conventional system has another drawback in that the pattern of the recorded ship's track together with the longitude and latitude line markers cannot be shifted to a desired position. If a shift were to be attempted, the same pattern would simply be reproduced at a different position on the recording paper even if the reference point is moved to a proper position. Furthermore, the reference point must be manually re-adjusted when the position of a ship goes beyond the boundary of the chart making it necessary to always begin plotting the position of the ship at an appropriate part of the recording paper.
Accordingly, an object of the invention is to provide a ship track indicating system which can electronically automatically indicate on the display surface of an indicator longitude and latitude line markers as well as a ship's track.
Another object of this invention is to provide a ship track indicating system which can automatically magnify or reduce the displayed pattern over the indicating surface of an indicator.
Yet another object of this invention is to provide a ship track indicating system which can automatically shift the displayed pattern to any desired position over the indicating surface of an indicator.
Still another object of this invention is to provide a ship track indicating system which can indicate movable cursor line markers which are parallel to the longitude and latitude line markers in addition to the ship's track with the longitude and latitude line markers extending over the display surface of an indicator.
A still further object of this invention is to provide a ship track indicating system which can indicate symbols corresponding to the cursor line markers parallel to the latitude and longitude line markers.
Moreover, an object of this invention is to provide a ship track indicating system which can automatically magnify or reduce the displayed pattern wherein the ship's track, the longitude and latitude line markers, and the cursor line markers and/or the symbols associated therewith are displayed.
A further object of this invention is to provide a a ship's track indicating system which can automatically shift the displayed pattern to a desired position wherein the ship's track, the longitude and latitude line markers, and the cursor line markers and/or the symbols associated therewith are displayed.
Another object of this invention is to provide a ship track indicating system which can automatically shift the displayed pattern to a proper position wherein the ship's track as well as the longitude and latitude line markers, the cursor line markers and associated symbols are still indicated when the present position of a ship goes beyond the display surface of the indicator.
One more object of this invention is to provide a moving body track indicating system which can electronically automatically indicate on the indicating surface of an indicator longitude and latitude line markers as well as a moving body's track.